Maybe this will help connect the passages for you...
The passion of Christ actually began at the Last Supper, where
the new covenant was established and instituted.
Only in the context of what began in the Upper Room the night before does it become clear: It refers to the Eucharistic sacrifice.
"Now as they were eating, Jesus took bread, and after blessing it broke it and gave it to the disciples, and said, 'Take, eat; this is my body.' And he took a cup, and when he had given thanks he gave it to them, saying, '
Drink of it, all of you, for this is my blood of the covenant, which is poured out for many for the forgiveness of sins.'" (
Mt. 26:26-28)
"And as they were eating, he took bread, and after blessing it broke it and gave it to them, and said, 'Take; this is my body.' And he took a cup, and when he had given thanks he gave it to them, and they all drank of it. And he said to them,
'This is my blood of the covenant, which is poured out for many.'" (
Mark 14:22-24)
"And he took bread, and when he had given thanks, he broke it and gave it to them, saying, 'This is my body, which is given for you. Do this in remembrance of me' And likewise the cup after they had eaten, saying, '
This cup that is poured out for you is the new covenant in my blood.'" (
Luke 22:19-20)
Again, it is at this moment when the new Moses, Jesus Christ,
fulfills the type / figure of the old covenant of Moses in Exodus with the new reality of the Eucharistic sacrifice...
Exodus 24 (The figure) ---> The hill, the altar, the twelve, the blood, Moses, the covenant, the eating the drinking and communion with God ---> Points to the reality of the new now being fulfilled by Jesus Christ ---> The Upper Room, the altar, the twelve, the blood, the New Moses, the new covenant, the eating and drinking and communion with God.
Or:
Exodus 24 ---> The New Covenant / Testament
The hill ---> The Upper Room
The altar ---> The Table
The twelve pillars ---> The Twelve Apostles
The blood ---> The Blood of Christ
Moses ---> The New Moses, Jesus Christ
The covenant ---> The New Covenant
Eating and drinking and communion with God ---> Eating and drinking and communion with God
This is
finished (consummated) on the Cross on Good Friday. The Last Supper is what is consummated / completed /
finished when Jesus is on the cross. The Last Supper and Calvary are one single event. Christ is both the high priest and the victim (
Hebrews 9:11-12).
Your assertions are demonstrably erroneous for two reasons. First, according to Protestant theology, there is nothing to commemorate at that moment
because his sacrificial offering did not occur until the following day. Protestant theology says nothing was offered on Holy Thursday. Hence, you are commemorating that which did not yet occur!
Secondly, and more importantly, if the Eucharist is not the actual body and blood of Christ,
it would be the first time in all of salvation history where the figure of something would have surpassed the reality of it, thus rendering the Old Covenant of Exodus 24 exceeding the New Covenant of Jesus Christ.